upgrading stirgeman pants

Just in case you don't already know this, keep in mind that when you "upgrade" your pants, it's random which set you will get; there's even a chance he'll give you another set of level 20 pants. Also there is a chance he'll explode your pants and give you nothing at all in return.

To explain further:

Basically, it works like this. There's the current tier that your item is, and a distribution curve of how it could upgrade. There's an X% chance it can go up one level or down one level. There's an (X/2)% chance that it'll go up 2, or down 2, and so on. If you have the 2nd level pants, and it tells it to downgrade it 3 times, it'll get destroyed, because it can only go down one level, then there's no where else for it to go.

What's this mean? For the first level of item, there's an ENORMOUS chance it'll be destroyed. Once you manage to get it up to 2 or 3, then it's a lot less likely to happen, however it can still downgrade to a point where destruction is dangerously likely.

I'll just say this:
I tried to get the Stirgeman cape with the 120 HP on it. I destroyed over 25 capes and never got it. The capes were infinitely more common than the pants. Good luck.